Field of the Invention and Related Art Statement
The present invention relates to an optical information recording and/or reproducing apparatus comprising an optical means for projecting a light beam upon an optical record medium, and a driving means for driving the optical record medium with respect to an optical axis of the optical means to effect the information recording and/or reproduction.
Optical record media can be roughly classified into read-only type, write-once type and rewritable type. Each of these different types of record media includes a large sub-varieties whose characteristics are different from each other based upon construction, materials, etc. of each optical record medium.
In order to effect recording and/or reproduction accurately for different optical record media, it is necessary to adjust the power of a laser light beam which is made incident upon the record medium to an optimum value.
In Japanese Patent Application Laid-open Publication Kokai Sho No. 63-103446, there is disclosed an optical information recording and/or reproducing apparatus in which the writing power of the laser light is adjusted in accordance with identifying information provided on a carriage of a record medium, i.e. an optical disk. That is to say, the above information is directly written on the cartridge surface or a label having the information written thereon is applied on the cartridge surface. In Japanese Patent Application Laid-open Publication Kokai Sho No. 63-108539, there is described another known optical information recording and/or reproducing apparatus comprising a detector for reproducing the information recorded on a magnetic tape which is applied on the cartridge of a disk and the writing laser power is controlled in accordance with the information reproduced from the magnetic tape.
In the known optical information recording and/or reproducing apparatuses mentioned above, the operational condition data such as the optimum writing laser power, writing pulse duration and reading, laser power have been recorded on the cartridge of the record medium. Usually the record medium and the cartridge are manufactured separately, so that there might occur that the record medium denoted by the information recorded on the cartridge is not always identical with the actual record medium installed in the cartridge. Moreover, the information recorded on the cartridge is liable to be damaged and stained, and thus the information could not be reproduced correctly.
Further in the write-once type and rewritable type optical record media, there has been proposed to record the information about the optimum laser power, etc. in a control track of an optical record medium in accordance with a proposal (DP9171, DP10089) of ISO (International Organization for Standardization). The operational condition data recorded in the record medium is first read out and the writing laser power is set to the optimum value in accordance therewith. It should be noted that the operational condition may also include the optimum laser power for reading and optimum time durations of recording pulses.
In the above explained known optical information recording and/or reproducing apparatus, the operational condition data such as the optimum writing laser power, optimum reading laser power, writing pulse duration, etc. is recorded. These values are usually selected when the record medium is set on the standard apparatus. However, in practice, the optical information recording and/or reproducing apparatuses have different characteristics, so that the optimum operational conditions for the standard apparatus could not be suitable for particular apparatuses. The optical information recording and/or reproducing apparatuses have optical systems having different NA, laser light source (different wavelengths) and the methods of measuring the laser power are different from each other. Particularly, when optical information recording and/or reproducing apparatuses which use the same optical record medium are manufactured by different makers, the optimum operational conditions differ from each other.